Various web applications utilize some form of targeted advertising. For example, a search engine application might deliver advertisements based on the text entered in a search query. A user searching for “Hawaii” might be presented with advertisements for vacation packages to Hawaii, for example. An email application could deliver advertisements based on the content of the email message. However, such methods are limited by how well the interests of the user correlate with the text in a search query or in an email message. For example, an employee might receive many email messages about a work related issue, but have no interest in buying products related to his work. The employee might be much more interested in food, but it would be difficult to determine this from the email he receives. Improved methods of selecting and delivering targeted content are needed.